Photographic developer



veloping compositions. A

enema July 14, 194.;

. John David Kendall,

llfordpEngland, assignor to lliord Limited, llford, England, a British com-- a No Drawing; Application May In Great Britain 28, 1941, Serial July 10, 1940 13 Claims. (01. 95-8 8) This invention relates to'photographic development processes and in particular to the development of latentimages formed in silver halide photographic emulsions.

It is an object of this invention to provide a new series of compounds capable of acting as photographic developers. of this invention to provide still further object of the invention is to provide a substitute for Metol f (1-methyl-amino-4-hydroxybenzene) in photographic developers. other objects will appear hereinafter. According to this invention the development of latent images formed in photographic materials bearing silver halide emulsions is eiiected by treating the materials with a solution containing a 3-pyr azolidone of the general formula:

R1 where R1, R51 and R3 are the same or different and are hydrogen atoms or hydrocarbon groups, tor-instance, alkyl groups, e. g. methyl, ethyl, propyl, isopropyl or higher alkyl groups, aryl groups, e. g. phenyl and naphthyl groups or aralkyl groups,- e. g. benzyl groups. Such hydrocarbon substituent groups may themselves .be substituted; substituted with and Rs are hydrogen atoms are especially valuable developing agents according to this in vention.

. The 3- pyrazolidones may be prepared by yar- It is a further object i new photographic deions methods. Thus compoundsv in which R1 in the above atom maybe general formula is an hydrogen prepared by condensing hydrazine hydratewith an a-,B-oleflne carboxylic acid of the general formula:

' Ri I Brandt-coon Compounds in which R1 is a hydrocarbon group may be prepared by condensing the corresponding hydrocarbon-substituted hydrazine with a fi-halogen-substituted fatty acid of the general formula:

or iodine.

The developing agents of this invention may be employed indeveloping compositions in which they form the sole active developing agents or they may be employed in developing compositions which also contain other active developing agents. A particularly valuable developing agent according to this invention is 1-pheny1-3- pyrazolidone. This compound has developing qualities which somewhat resemble those 01 metol (1-methyl-amino-4-hydroxy-benzene sul- It hasla very low inertia period i. e.

phate). development sets in very rapidly, and it yields developed'images of soft contrast. satisfactorilyused as a'substitute for metol in all types of developing compositions in which metol has hitherto been employed. However,.

it presents the very distinct advantage over metol that, used as a substitute for metol in developing solutions containing other developers inaddition to the metol, e. g. hydroquinone or pyrogallic acid, it may trations much smaller than those in which metol is normally employed, whilst retaining similar developing properties. 7

Thus, for example, replacement of the metol in a metol-hydroquinone developer by about $5 to 6 of its weight of l-phenyl-3 pyrazolidone according to the particular developer composi .tion yields a developer of similar development characteristics to the initial metol-hydroquinone developer. I

The compounds of this invention may also be halogen atom, e. g. chlorine, bromine It may be be employed in concen- I employed as substitutes for part only of the metol in metol-type developers, and in general the compounds may be employed as additionsto all types of developer compositions where they serve as agents to decrease the inertia period of such developing compositions.

The following examples illustrate the invention:

EXAMPLE I In this example l-phenyl-a-pyrazolidone is employed as the sole developing agent.

Developer 1-phenyl-3-pyrazolidone grams 3' Sodium sulphite (crystalline) do 25 Sodium carbonate (crystalline) do 50 Potassium br do 0.5 Water to make up to ccs 500 For use, one part of this developer is diluted with three parts of water. It is a very soft-working 'developer giving results of a similar character to those obtained from a similar developer containing an equal weight of metol as the sole developing agent, but of softer contrast.

Exnnm: II

In this example 1-phenyl-3-pyrazolidone is used as a substitute for the metol in a metolhydroquinone developer.

. Developer 1-phenyl-3-pyrazolidone "grams" 0. 15 Sodium sulphite (crystalline) 2 do 75 Hydroquinone do 4 Sodium carbonate (crystalline) do 50 Potassium bromide do 1 Water to make up to ccs 500 .For use, one part of thisdeveloper is diluted with two parts of water. It yields results which are very closely similar to those obtained from a similar developer containing 1 gram of metol instead of the 0.15 gram of 1-phenyl-3-pyrazolidone. Thus it will be noted that by substituting for the metol in this standard type of metol-hydroquinone developer, V; of its weight of l-phenyl- 3- pyrazolidone, a developer'of very similar characteristics is obtained.

-' EXAMPLE III In this example, 1-phenyl-3-pyrazolidone is used as a substitute for the metol in a metolpyrogallic acid type of developer.

Developer Solution A:

1-phenyl-3-pyrazolidone grams 0.2 Potassium metabisulphite do 6 Pyrogallic acid do 6 Water to make up to ccs 500 Solution B:

Sodium carbonate (crystalline) grams 100 Water to make up to ccs 500 For use, equal parts of solutions A and B are mixed together. The developer has properties 'very' closelyvsimllar to those obtained from a corresponding developer containing 2 grams of metol instead 01' the 1 -phenyl,-3-pyrazolidone. In

EXAMPLE IV This illustrates the addition of 1-l henyl-3- pyrazolidone to a metol hydroquinone developer.

Developer 1-phenyl-3-pyrazolidone grams 1.0 Metol do 1. 0 Sodium suiphite (crystalline) do 75 Hydroquinone do 4 Sodium carbonate (crystalline) do Potassium-bromide do 1 Water to make up to ccs 500 For use, one part of this developer is diluted with 2 parts of water. I

This developer is much more rapid in action than a developer not containing the 1-phenyl-3- pyrazolidone but otherwise of the same composition. The increase in the speed of development due to the presence of the 1-phenyl-3- pyrazolidone in the above developer compositions is shown'by the following figures which were obtained 'on development 01 a fast panchromatic Thus it will be seen that the developer containing 1-phenyl-3-pyrazolidone gives an image of slightly higher contrast in two minutes development than is obtained in four minutes without the l-phenyl-3-pyrazolidone.

The foregoing examples are intended primarily to shew the variability of application of the developers and they all specify the compound 1- phenyl-3-pyrazolidone. It is to be understood however, that any other B-pyrazolidone included within the scope of this invention may be similarly employed. Thus, equal weight of l-p-tolyl- S-pyrazolidone, 1-p-chlorphenyl-3-pyrazolidone, and l-phenyl-5-methyl-3-pyrazolidone substituted for the l-phenyl-3-pyrazolidone of Example II above give developers of very similar character- Lil other words, by substituting .for the metol in this standard type of developer, only 6 of its weight of l-phenyl-a-pyrazolidone, a developer of very similar characteristics is obtained.

istics, the developed images obtained in the case of developers containing 1-p-chlorphenyl-3- pyrazolidone and 1-phenyl-5-methyl-3-pyrazolidone being of somewhat softer contrast.

What I claim .is:

1. A photographic developing composition containing a 3-pyrazolidone of the general formula:

where R1, R2 and Rs are selected from the class consisting of hydrogen atoms and hydrocarbon groups.

2. A photographic developing composition coni where R1, R2 and R3 ar taining hydroquinone and a 3-pyrazolidone of the general formula: v

e selected from the class consisting of hydrogen atoms and hydrocarbon groups.

3. A photographic developing composition containing pyrogallic acid and a 3-pyrazolidone of l the general formula:

where R1, R2 and R3 are selected from the class consisting of hydrogen atoms and hydrocarbon groups.

4. A photographic dev'eloping composition containing 1-methylamino-4-hydroxy benzene, hydroquinone and a 3-pyrazolidone 'of the general formula: I

e selected from the class atoms and hydrocarbon where R1, R2 and R3 ar consisting of hydrogen groups.

5; A photographic developing composition containing' J,-phenyl-3-pyrazolidone.

6. A photographic developing composition con! talning l-phenyl-a-pyrazolidone and hydroquinone.

' pyrogallic acid. g

7. A photographic developing composition .'con taining '1-phenyl-3-pyraz'olidone and pyrogallic acid.

hydroxy benzene and hydroquinone.

9. An alkaline photographic developing composition containing an alkali metal sulflte, an

alkali metal carbonate and a 3-pyrazolidone ofthe general formula:

\CC.=Q R:

NH Br N 3-pyrazolidone of the general formula:

where R1, R2 and R3 are selected from the class consisting of hydrogen atoms and hydrocarbon groups.

11. A photographic containing an alkali metal sulflte, an' alkali metal carbonate, and 1-phenyl-3-pyrazolidone.

12. A photographic developing composition 1 containing an alkali metal sulfite,.an alkali metal carbonate,.; and 1-phenyl-3-pyrazdlidone and 13.-A photographic developing composition containing an alkali metal sulfite, an alkali metal carbonate, and 1-pheny1-3-pyrazolidone, l-methylamino-4-hydroxy benzene and hydroquinone. 7 JOHN DAVID KENDALL.

v 8. A photographic developing composition containing 1-phenyl-3-pyrazolidone, l-methylaminodeveloping composition 

